What do you mean with a language lock in address bar?
Are you using different keyboard layouts and regularly switch to another language or do you mean the language that is used in the user interface?
Can you attach a screenshot?
*http://en.wikipedia.org/wiki/Screenshot
*https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem
Use a compressed image type like PNG or JPG to save the screenshot.

Yep, I'm using different keyboard layouts and yes, I regularly switch to another language. But in address bar I use only english, but always forgot to change on english.
[http://screenshot.su/show.php?img=6d1ef2ecfc7ddebc5408505b02fbfac0.jpg It was there as grey lock icon with "En".]